Selection of Rigged Characters
Generally speaking you will use File&gt; Link to bring a mesh into another blend file. You then navigate to the .blend file, which will open up like a directory in the file browser. If the rig is well-designed, there will be a Group directory inside. Go into the group directory and select the group.

If there is no Group folder, navigate to the Object folder and Shift + LMB the objects that you want.

Linking provides several advantages. Not the least of which is that you can edit your rig without requiring any changes in your asset file. Invaluable when working with other people who are your modelers. However you could also Append which makes it so it points to the file, instead of copying it. This is useful working with other people, or when you what to change the asset directly.